Note 11 and Figure 6.6 on Pages 692-693: EPA’s RULE CLARIFYING ITS JURISDICTION OVER “WATERS OF THE UNITED STATES”

As the casebook notes, in April 2011 EPA and the U.S. Army Corps of Engineers issued proposed guidance on how to interpret the scope of federal jurisdiction over the “waters of the United States” in the wake of the Rapanos decision. Figure 6.6 summarizes the principal conclusions of this guidance. In September 2013 EPA’s Science Advisory Board released for public comment a new draft scientific report on “Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of the Scientific Evidence.” The report, based on review of more than 1,000 scientific studies, served as the basis for a new EPA rule to clarify the scope of federal jurisdiction under the Clean Water Act, which was proposed in April 2014 and finalized in May 2015. A copy of the report is available online at: http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=238345.

EPA summarizes the principal conclusions of the report as follows:

(1)Streams, regardless of their size or how frequently they flow, are connected to and have important effects on downstream waters. These streams supply most of the water in rivers, transport sediment and organic matter, provide habitat for many species, and take up or change nutrients that could otherwise impair downstream waters.

(2)Wetlands and open-waters in floodplains of streams and rivers and in riparian areas (transition areas between terrestrial and aquatic ecosystems) are integrated with streams and rivers. They strongly influence downstream waters by affecting the flow of water, trapping and reducing nonpoint source pollution, and exchanging biological species.

(3)Finally, there is insufficient information to generalize about wetlands and open-waters located outside of riparian areas and floodplains and their connectivity to downstream waters.

The “waters of the United States” rule has been challenged in several courts. The U.S. Court of Appeals for the Sixth Circuit has stayed the rule pending the outcome of the litigation. In January 2017 the U.S. Supreme Court agreed to decide whether the rule first should be challenged in the federal district courts. In National Association of Manufacturers v. Department of Defense, No. 16-299, the Court will decide this issue. The U.S. Court of Appeals for the Sixth Circuit has stayed the “waters of the U.S.” litigation pending the outcome of the Supreme Court case.

On February 28, 2017 President Donald Trump signed Executive Order 13,778 directing EPA Administrator Scott Pruitt to reconsider EPA’s “waters of the United States” rule. This rule, which was promulgated in 2015, is a product of EPA’s long-time efforts to clarify the reach of federal jurisdiction under the Clean Water Act. The rule was necessary because of the U.S. Supreme Court’s decision in Rapanos v. U.S., where the Court split 4-1-4. Four Justices, led by Justice Scalia, stated that the Clean Water Act did not apply to wetlands that are adjacent to the non-navigable tributaries of navigable waters. Four Justices stated that the Act did apply. Justice Kennedy, however, announced his own “significant nexus” test. Although Kennedy’s test was rejected by all eight other Justices, it became the deciding factor and EPA’s rule was intended to determine when such waters have a significant nexus to navigable waters. The new executive order directs EPA to consider adopting Justice Scalia’s “continuous surface connection” test that would radically restrict federal jurisdiction. However, since this test was rejected by a majority of the Court (Kennedy and the four dissenters), EPA would be on shaky legal grounds if it adopts it.

Notes 5 & 6 on Page 706: STATUS OF EPA’S “WATER TRANSFERS RULE”

As discussed in Note 5 of the casebook, in June 2008 EPA adopted a final rule excluding water transfers from NPDES permit requirements. 40 C.F.R. 122.3(i). As described in Note 6, challenges to this rule were filed in both federal district courts and U.S. Courts of Appeals because of uncertainty concerning which level of court would have initial jurisdiction to review the rule. In July 2008 the Judicial Panel on Multidistrict litigation consolidated the Court of Appeals challenges in the Eleventh Circuit (“Friends II”) where they were stayed while that court reviewed an appeal of a successful citizen suit against a transferor who did not have a permit (“Friends I”). The court reversed that judgment in Friends I by deferring to the newly promulgated water transfer rule, Friends of the Everglades v. South Florida Water Management District, 570 F. 3D 1210 (11th Cir. 2009), and the Supreme Court denied review in November 2010.

The 11th Circuit subsequently dismissed Friends II for lack of jurisdiction, holding that because the water transfers rule was not an effluent limit, permit issuance or denial, or other action covered by § 509‘s judicial review provisions, it cannot be reviewed initially in the U.S. Courts of Appeal. Friends of the Everglades v. U.S. EPA, 699 F.3d 1280 (11th Cir. 2012). EPA, which had wanted the Friends II court instead to uphold the validity of the water transfers rule, sought Supreme Court review of the Friends II decision because the agency believes that review of the rule should initially be available in the U.S. Courts of Appeal. On October 15, 2013 the Supreme Court announced that it would not review Friends II. The legality of the water transfers rule was then reviewed in federal district court in New York where challenges to it previously had been stayed. On March 28, 2014, Judge Kenneth M. Karas of that court struck down EPA’s water transfers rule, remanding it to the agency to develop a reasoned explanation for its interpretation of “navigable waters” in the Clean Water Act. Catskill Mountain Chapter of Trout Unlimited v. EPA, 2014 WL 1284544 (S.D.N.Y. 2014). This decision was then appealed to the U.S. Court of Appeals for the Second Circuit that, as mentioned in Note 5 on page 706, in 2006 held in the Trout Unlimited decision that water transfers required an NPDES permit.

On January 18, 2017, a panel of the Second Circuit upheld EPA’s water transfer rule in a 2-1 decision. Catskill Mountain Chapter of Trout Unlimited, Inc. v. EPA (Catskill III), 2017 WL 192707 (2d Cir. 2017). In an opinion by Judge Sack, the court held that because the Clean Water Act does not directly address the question whether NPDES permits are required for water transfers, EPA’s rule generally exempting them from permit requirements was entitled to Chevron deference. The court disagreed with the district court’s decision that the rule was unreasonable and therefore did not warrant deference. In dissent, Judge Chin argued “that the plain language and structure of the Act is unambiguous and clearly expresses Congress's intent to prohibit the transfer of polluted water from one water body to another distinct water body without a permit.” He maintained that “Congress did not intend to give a pass to interbasin transfers of dirty water, and excluding such transfers from permitting requirements is incompatible with the goal of the Act to protect our waters.”

Page 707: CAN A WATER TRANSFER QUALIFY AS THE “DISCHARGE OF A POLLUTANT”? - THE LOS ANGELES COUNTY FLOOD CONTROL DISTRICT CASE ON REMAND

As discussed in the casebook, in Los Angeles County Flood Control District v. Natural Resources Defense Council, Inc., 133 S.Ct. 710 (2013), the U.S. Supreme Court confirmed that “the transfer of polluted water between ‘two parts of the same water body’ does not constitute a discharge of pollutants under the [Clean Water Act].” The decision involved a lawsuit charging the flood control district with violating its stormwater discharge permits. On remand, on August 8, 2013, the U.S. Court of Appeals for the Ninth Circuit issued a decision finding as a matter of law that the flood control district violated its NPDES stormwater discharge permits. The decision represents a considerable victory for NRDC and indicates that the Supreme Court’s decision need not be an obstacles to enforcement of stormwater discharge permits.

.

Natural Resources Defense Council, Inc. v. County of Los Angeles,

725 F.3d 1194 (9th Cir. 2013)

Milan D. Smith, Jr., Circuit Judge:

Plaintiffs–Appellants Natural Resources Defense Council and Santa Monica Baykeeper (collectively, the Plaintiffs) filed suit against the County of Los Angeles and the Los Angeles County Flood Control District (collectively, the County Defendants) alleging that the County Defendants are discharging polluted stormwater in violation of the terms of their National Pollutant Discharge Elimination System (NPDES) permit, issued pursuant to the Federal Water Pollution Control Act (the Clean Water Act, Act, or CWA), 86 Stat. 816, codified as amended at 33 U.S.C. §§ 1251, et seq. The district court granted the County Defendants' motion for summary judgment, reasoning that Plaintiffs failed to prove that any individual defendant had discharged pollutants in violation of the Clean Water Act, where Plaintiffs' only evidence of violations was monitoring data taken downstream of the County Defendants' (and others') discharge points, as opposed to data sampled at the relevant discharge points themselves. On appeal, we affirmed the district court's judgment in part and reversed in part. Natural Res. Def. Council, Inc. v. Cnty. of L.A., 673 F.3d 880 (9th Cir.2011). On January 8, 2013, the Supreme Court reversed our judgment and remanded this case to us for further proceedings. L.A. Cnty. Flood Control Dist. v. Natural Res. Def. Council, Inc., 133 S.Ct. 710 (2013). On February 19, 2013, we ordered the parties to file supplemental briefs addressing the implications of the Supreme Court's ruling. Having considered the Supreme Court's ruling, the responses of the parties in their supplemental briefs, and other matters noted herein, we now conclude that the pollution exceedances detected at the County Defendants' monitoring stations are sufficient to establish the County Defendants' liability for NPDES permit violations as a matter of law. Accordingly, we once again reverse the district court's grant of summary judgment in favor of the County Defendants, and remand to the district court for a determination of the appropriate remedy for the County Defendants' violations.

FACTUAL BACKGROUND

I.Stormwater Runoff in Los Angeles County

Stormwater runoff is surface water generated by precipitation events, such as rainstorms, which flows over streets, parking lots, commercial sites, and other developed parcels of land. When stormwater courses over urban environs, it frequently becomes polluted with contaminants, such as “suspended metals, sediments, algae-promoting nutrients (nitrogen and phosphorus), floatable trash, used motor oil, raw sewage, [and] pesticides[.]” Envtl. Def. Ctr., Inc. v. EPA, 344 F.3d 832, 840 (9th Cir.2003). This polluted stormwater often makes its way into storm drains and sewers, which “generally channel collected runoff into federally protected water bodies,” id., such as rivers and oceans. Consequently, stormwater runoff has been recognized as “one of the most significant sources of water pollution in the nation, at times comparable to, if not greater than, contamination from industrial and sewage sources.” Id.

Los Angeles County (the County) is home to more than 10 million people and covers a sprawling amalgam of populous incorporated cities and significant swaths of unincorporated land. The Los Angeles County Flood Control District (the District) is a public entity governed by the Los Angeles County Board of Supervisors and the Los Angeles County Department of Public Works. The District comprises 84 cities and some unincorporated areas of the County. The County and the District are separate legal entities.

Each city in the District operates a municipal separate storm sewer system (ms4) that is composed of gutters, catch basins, storm drains, and pipes that collect and convey stormwater. The County also operates its own ms4 that primarily collects and conveys stormwater runoff in the unincorporated areas of the County. Each of these ms4s connects to the District's substantially larger ms4, an extensive flood-control and storm-sewer infrastructure consisting of approximately 500 miles of open channels and 2,800 miles of storm drains. Because a comprehensive map of the County Defendants' storm sewer system does not exist, no one knows the exact size of the LA MS4 or the locations of all of its storm drain connections and outfalls. But while the number and location of storm drains and outfalls are too numerous to catalog, it is undisputed that the LA MS4 collects and channels stormwater runoff from across the County. It is similarly undisputed that untreated stormwater is discharged from LA MS4 outfalls into various watercourses, including the Los Angeles and San Gabriel Rivers. These rivers, in turn, drain into several coastal waters, including, among others, the Santa Monica Bay and the Pacific Ocean.

II. The County Defendants' NPDES Permit

Section 301(a) of the CWA prohibits the “discharge of any pollutant” from any “point source” into “navigable waters” unless the discharge complies with certain other sections of the CWA .FN6See33 U.S.C. § 1311(a). One of those sections is section 402, which provides for the issuance of NPDES permits. 33 U.S.C. § 1342. In nearly all cases, an NPDES permit is required before anyone may lawfully discharge a pollutant from a point source into the navigable waters of the United States. See Arkansas v. Oklahoma, 503 U.S. 91, 101–02, 112 S.Ct. 1046, 117 L.Ed.2d 239 (1992); Environmental Law Handbook 323 (Thomas F.P. Sullivan ed., 21 st ed.2011).

Congress has empowered the EPA Administrator to delegate NPDES permitting authority to state agencies. 33 U.S.C. § 1342(b). Pursuant to this authority, the EPA has authorized the State of California to develop water quality standards and issue NPDES permits. Pursuant to the PorterCologne Water Quality Control Act, California state law designates the State Water Resources Control Board and nine regional boards as the principal state agencies charged with enforcing federal and state water pollution laws and issuing NPDES permits. SeeCal. Water Code §§ 13000 et seq. The entity responsible for issuing permits in the Los Angeles area is the California State Water Resources Control Board for the Los Angeles Region (the Regional Board).

On June 18, 1990, the Regional Board first issued an NPDES permit (the Permit) regulating stormwater discharges by the County, the District, and the 84 incorporated municipalities in the District (collectively, the Permittees). The Permit has subsequently been renewed or amended several times, and the version of the Permit at issue in this litigation came into force on December 13, 2001. The Permit covers all relevant discharges that occur “within the boundaries of the Permittee municipalities ... over which [the municipalities have] regulatory jurisdiction as well as unincorporated areas in Los Angeles County within the jurisdiction of the Regional Board.”

The Permit runs to 99 pages and contains a myriad of rules, regulations, and conditions regarding the Permittees' operation of the LA MS4. However, only two sets of the Permit's provisions are particularly relevant to this appeal; those contained in Part 2, titled “Receiving Water Limitations,” and those contained in the section titled “Monitoring and Reporting Program.”

Part 2 places limits on the type and amount of pollutants the Permittees may lawfully discharge from the LA MS4. Specifically, Part 2 prohibits “discharges from the [LA] MS4 that cause or contribute to the violation of the Water Quality Standards or water quality objectives.” The Permit defines “Water Quality Standards and Water Quality Objectives” as “water quality criteria contained in the Basin Plan, the California Ocean Plan, the National Toxics Rule, the California Toxics Rule, and other state or federal approved surface water quality plans.” Succinctly put, the Permit incorporates the pollution standards promulgated in other agency documents such as the Basin Plan, and prohibits stormwater discharges that “cause or contribute to the violation” of those incorporated standards. The Permit further provides that the Permittees “shall comply” with the LA MS4 discharge prohibitions outlined in Part 2 “through timely implementation of control measures and other actions to reduce pollutants in the[ir LA MS4] discharges....”

The Monitoring and Reporting Program complements Part 2. Under that program, the Permittees are required to monitor the impacts of their LA MS4 discharges on water quality and to publish the results of all pollution monitoring at least annually. The primary objectives of the monitoring program include “assessing compliance” with the Permit, “measuring and improving the effectiveness” of the Los Angeles Countywide Stormwater Quality Management Program (SQMP), and assessing the environmental impact of urban runoff on the receiving waters in the County.

One of the principal ways the Permittees are required to monitor their LA MS4 discharges is through mass-emissions monitoring. Mass-emissions monitoring measures all constituents present in water, and the readings give a cumulative picture of the pollutant load in a waterbody. The Permit requires the District, as Principal Permittee, to conduct mass-emissions monitoring at seven enumerated monitoring stations located throughout the County. The District is also responsible for analyzing the resulting data and submitting a comprehensive report of its findings. According to the Permit, the purpose of mass-emissions monitoring is to: (1) estimate the mass emissions from the LA MS4; (2) assess trends in the mass emissions over time; and (3) determine if the LA MS4 is contributing to exceedances of Water Quality Standards by comparing the monitoring results to the applicable pollution standards promulgated in the Basin Plan and similar documents.

The Permittees sited a mass-emissions monitoring station in both the Los Angeles and San Gabriel Rivers (collectively, the Monitoring Stations). The Los Angeles River monitoring station is located in a channelized portion of the Los Angeles River that runs through the City of Long Beach.The San Gabriel River monitoring station is located in a channelized portion of the San Gabriel River that runs through the City of Pico Rivera. The Monitoring Stations are located downstream of numerous LA MS4 outfalls controlled by the County Defendants and various other non-party Permittees.

Between 2002 and 2008, when this case was filed, the District published annual monitoring reports that contain the data that the District collected at the Monitoring Stations. According to those reports, the Monitoring Stations identified 140 separate exceedances of the Permit's water quality standards, including excessive levels of aluminum, copper, cyanide, zinc, and fecal coliform bacteria in both the Los Angeles and San Gabriel Rivers. The County Defendants do not dispute the accuracy of the monitoring data.

PROCEDURAL BACKGROUND

Using the monitoring data self-reported by the District, Plaintiffs cataloged the water quality exceedances measured in various receiving waters in the County. Beginning on May 31, 2007, Plaintiffs sent a series of notice letters to the County Defendants informing them that Plaintiffs believed that they were violating the terms of the Permit. Specifically, Plaintiffs contended that the water quality exceedances documented in the District's monitoring reports demonstrated liability under the CWA. Dissatisfied with the County Defendants' response to these letters, Plaintiffs brought this citizen-enforcement action on March 3, 2008. After the district court dismissed certain elements of the Plaintiffs' initial complaint because notice of the Permit violations was defective, Plaintiffs sent the County Defendants an adequate notice letter on July 3, 2008.

Plaintiffs filed their First Amended Complaint on September 18, 2008. In the complaint, Plaintiffs asserted six causes of action under the CWA. Four of the Plaintiffs' claims, which the district court designated the “Watershed Claims,” were initially before us on appeal. The first three Watershed Claims allege that, beginning in 2002 or 2003, the County Defendants caused or contributed to exceedances of water quality standards in the Santa Clara River (Claim 1), the Los Angeles River (Claim 2), and the San Gabriel River (Claim 3), in violation of 33 U.S.C. §§ 1311(a), 1342(p). The fourth Watershed Claim alleges that, beginning in 2002, County Defendants caused or contributed to exceedances of the water quality standards and violated the total maximum daily load limits in Malibu Creek. All of the Watershed Claims rest on the same premise: (1) the Permit incorporates water-quality limits for each receiving water body; (2) massemissions monitoring stations have recorded pollutant loads in the receiving water bodies that exceed those permitted under the relevant standards; (3) an exceedance constitutes non-compliance with the Permit and, thereby, the Clean Water Act; and (4) County Defendants, as holders of the Permit and joint operators of the LA MS4, are liable for these exceedances under the Act.

Early in the litigation, the district court bifurcated liability and remedy, and all proceedings related to remedy were stayed until liability was determined. On March 2, 2010, the district court denied all parties' cross-motions for summary judgment with regard to liability. NRDC v. Cnty. of L.A., No. CV 08–1467–AHM, 2010 WL 761287 (C.D.Cal. Mar. 2, 2010), amended on other grounds,2011 WL 666875 (C.D.Cal. Jan. 27, 2011). Although the district court accepted Plaintiffs' arguments that the Permit “clearly prohibits ‘discharges from the [LA] MS4 that cause or contribute to the violation of Water Quality Standards or water quality objectives,’ “ 2010 WL 761287, at 6, and that massmonitoring stations “are the proper monitoring locations to determine if the [LA] MS4 is contributing to exceedances” of the Water Quality Standards or water quality objectives, id., the district court held that Plaintiffs were improperly attempting to use the District's self-reported monitoring data to establish liability without presenting evidence that any individual defendant was discharging pollutants that “cause[d] or contribute[d] to the violation” of the water quality standards. Id. The district court observed that although “the District is responsible for the pollutants in the [LA] MS4” at the time they pass the Monitoring Stations, “that does not necessarily determine the question of whether the water passing by these points is a ‘discharge’ within the meaning of the Permit and the Clean Water Act.” Id. at 7. Unable to determine whether any of the County Defendants' upstream LA MS4 outflows were contributing polluted stormwater to navigable waters, the district court stated that “Plaintiffs would need to present some evidence (monitoring data or an admission) that some amount of a standardsexceeding pollutant is being discharged through at least one District outlet.” Id. at 8.

Following supplemental briefing, the district court again determined that “Plaintiffs failed to present evidence that the standards-exceeding pollutants passed through the Defendants' [LA] MS4 outflows at or near the time the exceedances were observed. Nor did Plaintiffs provide any evidence that the mass emissions stations themselves are located at or near a Defendant's outflow.” The district court thus entered summary judgment for the County Defendants on the Watershed Claims.

On June 9, 2010, the district court entered a partial final judgment on the Watershed Claims under Fed.R.Civ.P. 54(b). The court reasoned that an interlocutory appeal was appropriate because the Watershed Claims are “factually and legally severable” from the Plaintiffs' other claims and “[t]he parties and the Court would benefit from appellate resolution of the central legal question underlying the watershed claims: what level of proof is necessary to establish defendants' liability.” The Plaintiffs timely appealed.

On appeal, the Plaintiffs pressed the same legal argument they advanced in the district court: that the data published in the County Defendants' annual monitoring reports—data which shows undisputed pollution exceedances at the massemissions monitoring stations—conclusively establishes the County Defendants' liability for Permit violations as a matter of law. Like the district court, we rejected this contention and held that the Plaintiffs must submit at least some additional proof of the County Defendants' individual contributions to the measured Permit violations. See Natural Res. Def. Council, 673 F.3d at 898 (noting that “the Clean Water Act does not prohibit ‘undisputed’ exceedances; it prohibits ‘discharges' that are not in compliance with the Act.... While it may be undisputed that exceedances have been detected, responsibility for those exceedances requires proof that some entity discharged a pollutant.”).

Nonetheless, we held the District liable for CWA violations in the Los Angeles and San Gabriel Rivers because we concluded that the mass-emissions monitoring stations for each river are “located in a section of the [LA] MS4 owned and operated by the District” and that “when pollutants were detected, they had not yet exited the point source into navigable waters.” Id. at 899. We further clarified that “[t]he [relevant] discharge from a point source occurred when the still-polluted stormwater flowed out of the concrete channels where the Monitoring Stations are located, through an outfall, and into the navigable waterways. We agree with Plaintiffs that the precise location of each outfall is ultimately irrelevant because there is no dispute that [the LA] MS4 eventually adds stormwater to the Los Angeles and San Gabriel Rivers downstream from the Monitoring Stations.” Id. at 900.

On October 11, 2011, the District filed a petition for writ of certiorari, which was granted in part on June 25, 2012. The Supreme Court granted review in order to answer a single question: “Under the CWA, does a discharge of pollutants occur when polluted water flows from one portion of a river that is navigable water of the United States, through a concrete channel or other engineered improvement in the river, and then into a lower portion of the same river?” L.A. Cnty. Flood Control Dist., 133 S.Ct. at 712–13 (internal quotation marks omitted). The Court answered in the negative, and re-affirmed its holding in S. Fla. Water Mgmt. Dist. v. Miccosukee Tribe of Indians, 541 U.S. 95 (2004), that “pumping polluted water from one part of a water body into another part of the same body is not a discharge of pollutants under the CWA.” The Court did not address any other basis for the District's potential liability for Permit violations and instead reversed our prior judgment and remanded this case to us for additional proceedings.

JURISDICTION AND STANDARD OF REVIEW

We have jurisdiction under 28 U.S.C. § 1291. We review the district court's grant of summary judgment de novo.

DISCUSSION

I.

Plaintiffs return from the Supreme Court with the same argument they have consistently advanced throughout this litigation—that the County Defendants' monitoring data establishes their liability for Permit violations as a matter of law. We previously rejected this argument, see Natural Res. Def. Council, 673 F.3d at 898, and the Supreme Court explicitly declined to address it.

On remand, the County Defendants argue that we may not reconsider our earlier decision because it has become “final,” and because “reconsideration of Appellants' monitoring argument would fly in the face of the finality given to decisions of this Court after denial of rehearing or expiration of the time in which to seek such further review.” Alternatively, the County Defendants argue that our earlier disposition should be left undisturbed because it has become the law of the case. The County Defendants are mistaken on both counts.

Where a permittee discharges pollutants in compliance with the terms of its NPDES permit, the permit acts to “shield” the permittee from liability under the CWA. 33 U.S.C. § 1342(k). The permit shield is a major benefit to a permittee because it protects the permittee from any obligation to meet more stringent limitations promulgated by the EPA unless and until the permit expires. See Piney Run Pres. Ass'n v. Cnty. Comm'rs of Carroll Cnty., 268 F.3d 255, 266–69 (4th Cir.2001); see also The Clean Water Act Handbook 67 (Mark A. Ryan ed., 3rd ed.2011). Of course, with every benefit comes a cost: a permittee violates the CWA when it discharges pollutants in excess of the levels specified in the permit, or where the permittee otherwise violates the permit's terms.

Plaintiffs allege that the County Defendants are violating the terms of the Permit by discharging pollutants into the Los Angeles and San Gabriel Rivers in excess of the permitted levels. County Defendants do not dispute that they are discharging pollutants from the LA MS4 into these rivers. Nor can the County Defendants dispute that their own monitoring reports demonstrate that pollution levels recorded at the Monitoring Stations are in excess of those allowed under the Permit. Rather, the County Defendants focus on their perception of the evidentiary burden Plaintiffs must satisfy in order to hold any individual defendant liable for these pollution exceedances. Plaintiffs contend that they may rely exclusively on the District's monitoring reports to establish liability. County Defendants, however, argue that they cannot be held liable for Permit violations based solely on the data published in the District's monitoring reports because: (1) the mass-emissions monitoring required under the Permit was “neither designed nor intended” to measure the compliance of any Permittee; and (2) the monitoring data cannot parse out precisely whose discharge(s) contributed to any given exceedance because the Monitoring Stations sample pollution levels downstream from a legion of discharge points (e.g., LA MS4 outfalls) controlled by various Permittees and other non-party entities, as opposed to at the discharge points themselves.

To resolve the parties' contentions, we must interpret the language of the Permit. Although the NPDES permitting scheme can be complex, a court's task in interpreting and enforcing an NPDES permit is not—NPDES permits are treated like any other contract. See Nw. Envtl. Advocates, 56 F.3d at 982 (“We review the district court's interpretation of the 1984 permit as we would the interpretation of a contract or other legal document.”). If the language of the permit, considered in light of the structure of the permit as a whole, “is plain and capable of legal construction, the language alone must determine the permit's meaning.” Piney Run Pres. Ass'n, 268 F.3d at 270 (citation omitted). If, however, the permit's language is ambiguous, we may turn to extrinsic evidence to interpret its terms. Id. Our sole task at this point of the case is to determine what Plaintiffs are required to show in order to establish liability under the terms of this particular NPDES permit.

A.The Plain Language of the Permit

“[NPDES permit] terms are to be given their ordinary meaning, and when the terms of a [permit] are clear, the intent of the parties must be ascertained from the [permit] itself.” Klamath Water Users Protective Ass'n. v. Patterson, 204 F.3d 1206, 1210 (9th Cir.1999). Plaintiffs argue that the text of the County Defendants' Permit is clear, and provides that the District's mass-emissions monitoring data will be used to assess the County Defendants' compliance with the Permit, and particularly Part 2, which prohibits “discharges from the [LA] MS4 that cause or contribute to the violation of Water Quality Standards or water quality objectives.” The County Defendants dispute this notion, and first claim that the District's mass-emissions monitoring is intended to serve only a hortatory purpose. As County Defendants state, “the mass emission monitoring program ... neither measures nor was designed to measure any individual permittee's compliance with the Permit.” This argument is clearly belied by the text of the Permit and is rejected.

The Permit establishes a “Monitoring and Reporting Program” with the stated objectives of both characterizing stormwater discharges and assessing compliance with waterquality standards. The Permit language could not be more explicit in this regard, stating that “[a]ssessing compliance with this [Permit]” is one of the “primary objectives of the Monitoring Program.” “The fact that the parties dispute a [permit's] meaning does not establish that the [permit] is ambiguous; it is only ambiguous if reasonable people could find its terms susceptible to more than one interpretation.” Klamath Water Users Protective Ass'n, 204 F.3d at 1210. No reasonable person could find even the slightest ambiguity in the phrase “[t]he primary objectives of the Monitoring Program include, but are not limited to: Assessing compliance with this [Permit].” Consequently, we decline to embrace the County Defendants' initial argument that “the mass-emission monitoring stations, as a matter of fact, do not assess the compliance of any permittee with the Permit....”

County Defendants' alternative argument, while more facially appealing, fares no better. Specifically, the County Defendants point to certain Permit language they claim shows that the Regional Board did not intend for the mass-emissions monitoring data to be used to establish liability for Permit violations. For instance, the County Defendants note that the Permit provides that “[e]ach permittee is responsible only for a discharge for which it is the operator.” County Defendants also cite language in Part 2 that reads: “Discharges from the [LA] MS4 of storm water, or non-storm water, for which a Permittee is responsible for [sic], shall not cause or contribute to a condition of nuisance.” The County Defendants read this language as precluding a finding of liability against them—or any other Permittee—without independent monitoring data establishing that discharges from a particular entity's ms4 outfalls exceeded standards.

The County Defendants' interpretation of the Permit ultimately must be rejected because it would create an unreasonable result. Reading the clause that “[e]ach permittee is responsible only for a discharge for which it is the operator” to preclude use of the mass-emission monitoring data to “assess [ ] compliance with this [Permit]” would render the monitoring provisions of the Permit largely meaningless. Under the County Defendants' reading of the Permit, individual Permittees could discharge an unlimited amount of pollutants from the LA MS4 but never be held liable for those discharges based on the results of the mass-emissions monitoring, even though that monitoring is explicitly intended to assess whether Permittees are in compliance with Part 2's discharge limitations. We are unwilling to accept such a strained interpretation. A better reading of the Permit's putatively conflicting provisions, therefore, is the one proposed by Plaintiffs. Limiting a Permittee's responsibility to “discharge[s] for which it is the operator” applies to the appropriate remedy for Permit violations, not to liability for those violations. Indeed, Plaintiffs' reading is consistent with the remedial scheme of the Permit itself. If the LA MS4 is found to be contributing to water quality violations, each Permittee must take appropriate remedial measures with respect to its own discharges. Thus, a finding of liability against the County Defendants would not, as defendants argue, hold any County Defendant responsible for discharges for which they are not “the operator.”

In sum, and contrary to the County Defendants' contentions, the language of the Permit is clear—the data collected at the Monitoring Stations is intended to determine whether the Permittees are in compliance with the Permit. If the District's monitoring data shows that the level of pollutants in federally protected water bodies exceeds those allowed under the Permit, then, as a matter of permit construction, the monitoring data conclusively demonstrate that the County Defendants are not “in compliance” with the Permit conditions. Thus, the County Defendants are liable for Permit violations.

A.Extrinsic Considerations

Although we believe the plain language of the Permit clearly contemplates that the County Defendants' monitoring data will be used to assess Permit compliance (i.e., establish liability for CWA violations), we note that numerous extrinsic considerations also undercut the County Defendants' position.

First and foremost, the Clean Water Act requires every NPDES permittee to monitor its discharges into the navigable waters of the United States in a manner sufficient to determine whether it is in compliance with the relevant NPDES permit. 33 U.S.C. § 1342(a)(2); 40 C.F.R. § 122.44(i)(1) (“[E]ach NPDES permit shall include conditions meeting the following ... monitoring requirements ... to assure compliance with permit limitations.”). That is, an NPDES permit is unlawful if a permittee is not required to effectively monitor its permit compliance. See40 C.F.R. § 122.26(d)(2)(i)(F) (“Permit applications for discharges from large and medium municipal storm sewers ... shall include ... monitoring procedures necessary to determine compliance and noncompliance with permit conditions....”). As previously noted, the County Defendants contend that the mass-emissions monitoring program “neither measures nor was designed to measure any individual permittee's compliance with the Permit.” But if the County Defendants are correct, the Permit would be unlawful under the CWA. We must interpret the provisions of the Permit like any other contract and reject an interpretation that would render the Permit unenforceable.

Second, the County Defendants' position has been explicitly rejected by the Regional Board, the entity that issued the Permit. This is important because one of our obligations in interpreting an NPDES permit is “to determine the intent of the permitting authority....” Piney Run Pres. Ass'n, 268 F.3d at 270. Thus, we give significant weight to any extrinsic evidence that evinces the permitting authority's interpretation of the relevant permit. See Nw. Envtl. Advocates, 56 F.3d at 985 (relying on “significant evidence from [the state permitting agency], the permit author,” to determine the proper scope of an NPDES permit).

Here, the record contains an amicus brief filed by the Regional Board in a lawsuit nearly identical to this one. In that suit, these same Plaintiffs sued the City of Malibu, one of the County Defendants' co-permittees, for violating the NPDES Permit at issue in this case. In its brief, the Regional Board stated its position that:

The Permit recognizes that the interconnected nature of the system means that it may be difficult to determine exactly where [pollutants] originated within the [LA] MS4. This does not mean, however, that the Permit assumes only one permittee may be responsible. Instead, it recognizes that in such an integrated storm sewer system, one or more Permittees may have caused or contributed to violations.... Having constructed a joint sewer system that, by design, co-mingles the [Permittees'] discharges, they cannot avoid enforcement because one cannot determine the original source of pollutants in the waste stream.

The Regional Board also noted that “the monitoring program that the permittees requested (and were granted) does not readily generate the permittee-by-permittee outfall data that the [County Defendants] would require as a precondition to enforcement.” As a result, the Regional Board disagreed with any construction of the Permit that would require individualized proof of a Permittees' discharges in order to establish liability. Simply put, the Regional Board indicated that it “does not agree” that the “burden [of proving Permit violations] rests upon the enforcing entity.” Although we do not defer to the Regional Board's interpretation of the Permit, see Orthopaedic Hosp. v. Belshe, 103 F.3d 1491, 1495 (9th Cir.1997), its rejection of the County Defendants' position is clearly instructive.

Finally, the County Defendants' arguments run counter to the purposes of the CWA, and ignore the inherent complexity of ensuring an ms4's compliance with an NPDES permit that covers thousands of different point sources and outfalls. As we have previously recognized, “[t]he NPDES program fundamentally relies on self-monitoring.” Sierra Club v. Union Oil Co. of Cal., 813 F.2d 1480, 1491 (9th Cir.1987), vacated and remanded on other grounds,485 U.S. 931(1988), and reinstated and amended by853 F.2d 667 (9th Cir.1988). Congress' purpose in adopting this self-monitoring mechanism was to promote straightforward enforcement of the Act. See id. at 1492 (noting that Congress wished to “avoid the necessity of lengthy fact finding, investigations, and negotiations at the time of enforcement. Enforcement of violations of requirements under this Act should be based on relatively narrow fact situations requiring a minimum of discretionary decision making or delay”) (quoting S.Rep. No. 92–414, 92nd Cong., 1st Sess. 64, reprinted in 1972 U.S.Code Cong. & Ad. News 3668, 3730)). Or, as one treatise writer has described enforcement of the Act:

The CWA is viewed by many as the easiest of the federal environmental statutes to enforce. This is because persons regulated under the act normally must report their own compliance and noncompliance to the regulating agency. For example, holders of NPDES permits must file periodic discharge monitoring reports (or DMRs), which must contain the results of all monitoring

of discharges, and must indicate where those discharges exceed permit limitations.... Thus, enforcement actions may be brought based on little, if anything, more than the DMRs and other reports submitted by the permittee itself.

Environmental Law Handbook at 357–58.

Admittedly, regulating pollution from ms4s is substantially more complicated than regulating pollution from a few defined point sources. Like the LA MS4 at issue here, municipal separate storm sewer systems often cover many square miles and comprise numerous, geographically scattered, and sometimes uncharted sources of pollution, including streets, catch basins, gutters, man-made channels, and storm drains. Faced with the difficult task of regulating millions of storm-sewer point sources, Congress amended the CWA in 1987 to grant the EPA the express authority to create a separate permitting program for ms4s. 33 U.S.C. § 1342(p)(2), (3). In enacting these amendments, Congress recognized that for large urban areas like Los Angeles, ms4 permitting cannot be accomplished on a source-by-source basis. The amendments therefore give the EPA, or a state like California to which the EPA has delegated permitting authority, broad discretion to issue permits “on a system-wide or jurisdiction-wide basis,” 40 C.F.R. § 122.26(a)(1)(v), rather than requiring cities and counties to obtain separate permits for millions of individual stormwater discharge points. This increased flexibility is crucial in easing the burden of issuing stormwater permits for both permitting authorities and permittees.

But while otherwise more flexible than the traditional NPDES permitting system, nothing in the ms4 permitting scheme relieves permittees of the obligation to monitor their compliance with their NPDES permit in some fashion. See33 U.S.C. § 1342(a)(2) (“The Administrator shall prescribe conditions for [NPDES] permits to assure compliance with the requirements of [the permit], including conditions on data and information collection, reporting, and such other requirements as he deems appropriate.”); 40 C.F.R. § 122.44(i)(1) (establishing that every permit “shall include” monitoring “[t]o assure compliance with the permit limitations”). Rather, EPA regulations make clear that while ms4 NPDES permits need not require monitoring of each stormwater source at the precise point of discharge, they may instead establish a monitoring scheme “sufficient to yield data which are representative of the monitored activity.... ” 40 C.F.R. § 122.48(b) (emphasis added). In fact, EPA regulations require permittees, like the County Defendants here, to propose a “monitoring program for representative data collection for the term of the permit that describes the location of outfalls or field screening points to be sampled (or the location of instream stations )” and explain “why the [chosen] location is representative ....“ 40 C.F.R. § 122.26(d)(2)(iii)(D) (emphases added). Here, the County Defendants did just that. County Defendants themselves chose the locations of the Monitoring Stations, locations that are downstream from a significant number of their outfalls. And, as required by law, the County Defendants chose locations that they certified were necessarily “representative” of the monitored activity ( i.e ., the Permittees' discharges of stormwater runoff into the navigable waters of the United States). Now, however, County Defendants claim that their compliance with the Permit cannot be measured using the results of the representative monitoring they themselves agreed to, that the Regional Board approved, and that the Permit itself contemplates is to be used to assess compliance with its terms. We take this opportunity to reevaluate and reject County Defendants' arguments.

CONCLUSION

Because the results of County Defendants' pollution monitoring conclusively demonstrate that pollution levels in the Los Angeles and San Gabriel Rivers are in excess of those allowed under the Permit, the County Defendants are liable for Permit violations as a matter of law. This case is remanded to the district court for further proceedings consistent with this opinion, including a determination of the appropriate remedy for the County Defendants' violations.

Note 7, pages 716-717: STORMWATER DISCHARGES FROM LOGGING ROADS

As mentioned in the seventh edition of the casebook, in 2013 the U.S. Supreme Court reversed a decision by the U.S. Court of Appeals for the Ninth Circuit that had required the operators of logging roads to obtain NPDES permits for stormwater discharges from them. The Ninth Circuit had held that such stormwater discharges were not exempt under the 1987 amendments because they were the product of “industrial activity” covered by the Act. For those who wish to explore this issue in more depth, an edited excerpt of the Court’s decision is reproduced below.

These cases present the question whether the Clean Water Act (Act) and its implementing regulations require permits before channeled stormwater runoff from logging roads can be discharged into the navigable waters of the United States. Under the statute and its implementing regulations, a permit is required if the discharges are deemed to be “associated with industrial activity.” 33 U.S.C. § 1342(p)(2)(B). The Environmental Protection Agency (EPA), with the responsibility to enforce the Act, has issued a regulation defining the term “associated with industrial activity” to cover only discharges “from any conveyance that is used for collecting and conveying storm water and that is directly related to manufacturing, processing or raw materials storage areas at an industrial plant.” 40 C.F.R. § 122.26(b)(14) (2006). The EPA interprets its regulation to exclude the type of stormwater discharges from logging roads at issue here. For reasons now to be explained, the Court concludes the EPA's determination is a reasonable interpretation of its own regulation; and, in consequence, deference is accorded to the interpretation under Auer v. Robbins,519 U.S. 452, 461 (1997).

I

A

Congress passed the Clean Water Act in 1972 to “restore and maintain the chemical, physical, and biological integrity of the Nation's waters.” 86 Stat. 816, 33 U.S.C. § 1251(a). A central provision of the Act is its requirement that individuals, corporations, and governments secure National Pollutant Discharge Elimination System (NPDES) permits before discharging pollution from any point source into the navigable waters of the United States. See §§ 1311(a)1362(12)EPA v. California ex rel. State Water Resources Control Bd., 426 U.S. 200, 205 (1976). The Act defines “point source” as

“any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft, from which pollutants are or may be discharged. This term does not include agricultural stormwater discharges and return flows from irrigated agriculture.” § 1362(14).

When the Act took effect, the EPA found it difficult to process permit applications from countless owners and operators of point sources throughout the country. The agency issued regulations exempting certain types of point-source discharges from the NPDES permitting scheme, but in 1977 those directives were found invalid. The Court of Appeals for the District of Columbia Circuit ruled that the statute did not give the EPA “authority to exempt categories of point sources from the permit requirements” of the Act. Natural Resources Defense Council, Inc. v. Costle, 568 F.2d 1369, 1377. In response the EPA issued new regulations to define with more precision which categories of discharges qualified as point sources in the first place. Among these regulations was the so-called Silvicultural Rule. This rule is at issue here. It provides:

“ Silvicultural point source means any discernible, confined and discrete conveyance related to rock crushing, gravel washing, log sorting, or log storage facilities which are operated in connection with silvicultural activities and from which pollutants are discharged into waters of the United States. The term does not include non-point source silvicultural activities such as nursery operations, site preparation, reforestation and subsequent cultural treatment, thinning, prescribed burning, pest and fire control, harvesting operations, surface drainage, or road construction and maintenance from which there is natural runoff.” 40 C.F.R. § 122.27(b)(1).

Under the quoted rule, any discharge from a logging-related source that qualifies as a point source requires an NPDES permit unless some other federal statutory provision exempts it from that coverage. In one such provision, 33 U.S.C. § 1342(p), Congress has exempted certain discharges of stormwater runoff. The statutory exemptions were considered necessary because, from the outset, the EPA had encountered recurring difficulties in determining how best to manage discharges of this kind. See, e.g., Natural Resources Defense Council, Inc. v. EPA, 966 F.2d 1292, 1295–1296 (C.A.9 1992). In 1987, Congress responded to these problems and adopted various stormwater-related amendments to the Act. § 405, 33U.S.C. § 1342(p).

The 1987 amendments exempt from the NPDES permitting scheme most “discharges composed entirely of stormwater.” § 1342(p)(1). The general exemption, however, does not extend to all stormwater discharges. As relevant here, Congress directed the EPA to continue to require permits for stormwater discharges “associated with industrial activity.” § 1342(p)(2)(B). The statute does not define that term, but the EPA adopted a regulation (hereinafter Industrial Stormwater Rule) in which it defined it as

“the discharge from any conveyance that is used for collecting and conveying storm water and that is directly related to manufacturing, processing or raw materials storage areas at an industrial plant. The term does not include discharges from facilities or activities excluded from the NPDES program under this part 122. For the categories of industries identified in this section, the term includes, but is not limited to, storm water discharges from ... immediate access roads and rail lines used or traveled by carriers of raw materials, manufactured products, waste material, or by-products used or created by the facility....” 40 C.F.R. § 122.26(b)(14) (2006).

The Industrial Stormwater Rule also specified that, with one exception not relevant here, “[f]acilities classified as Standard Industrial Classificatio[n] 24” are “considered to be engaging in ‘industrial activity’ for purposes of paragraph (b)(14).” Ibid. The Standard Industrial Classifications are a system used by federal agencies to categorize firms engaged in different types of business activity. Standard Industrial Classification 24 identifies industries involved in the field of “Lumber and Wood Products.” This includes the “Logging” industry, defined as “[e]stablishments primarily engaged in cutting timber and in producing ... primary forest or wood raw materials.” Ibid.

On November 30, 2012—three days before the instant cases were argued in this Court—the EPA issued its final version of an amendment to the Industrial Stormwater Rule. The amendment was the agency's response to the Court of Appeals' ruling now under review. The amended version seeks to clarify the types of facilities within Standard Industrial Classification 24 that are deemed to be engaged in industrial activity for purposes of the rule. The amended Industrial Stormwater Rule does not cover all facilities within Standard Industrial Classification 24. It limits covered stormwater discharges to

. . . It is fair to say the purpose of the amended regulation is to bring within the NPDES permit process only those logging operations that involve the four types of activity (rock crushing, gravel washing, log sorting, and log storage facilities) that are defined as point sources by the explicit terms of the Silvicultural Rule.

Up to this stage in the litigation, of course, the cases have been concerned with the Industrial Stormwater Rule before the amendment adopted on November 30, 2012. The amended regulation will determine whether from this point forward NPDES permits will be required for the stormwater discharges at issue. . . .

B

At issue are discharges of channeled stormwater runoff from two logging roads in Oregon's Tillamook State Forest, lying in the Pacific Coast Range about 40 miles west of Portland. Petitioner Georgia–Pacific West, along with other logging and paper-products companies, has a contract with the State of Oregon to harvest timber from the forest. It uses the roads for that purpose. When it rains (which it does often in the mountains of northwest Oregon, averaging in some areas more than 100 inches per year), water runs off the graded roads into a system of ditches, culverts, and channels that discharge the water into nearby rivers and streams. The discharges often contain large amounts of sediment, in the form of dirt and crushed gravel from the roads. There is evidence that this runoff can harm fish and other aquatic organisms.

In September 2006, respondent Northwest Environmental Defense Center (NEDC) filed suit in the United States District Court for the District of Oregon. It invoked the Clean Water Act's citizen-suit provision, 33 U.S.C. § 1365, and named as defendants certain firms involved in logging and paper-products operations (including petitioner Georgia–Pacific West), as well as state and local governments and officials (including the State Forester of Oregon, who is now petitioner Doug Decker). The suit alleged that the defendants caused discharges of channeled stormwater runoff into two waterways—the South Fork Trask River and the Little South Fork Kilchis River. The defendants had not obtained NPDES permits, and so, the suit alleged, they had violated the Act.

The District Court dismissed the action for failure to state a claim. It concluded that NPDES permits were not required because the ditches, culverts, and channels were not point sources of pollution under the Act and the Silvicultural Rule. The Court of Appeals for the Ninth Circuit reversed. It relied upon three principal propositions. First, it held that the District Court had subject-matter jurisdiction under § 1365 notwithstanding a different provision of the Act, 33 U.S.C. § 1369(b)(1), limiting judicial review of EPA regulations. Second, the Court of Appeals held that while the EPA's Silvicultural Rule is ambiguous on the question whether the conveyances at issue are point sources, those conveyances must be deemed point sources under the rule in order to give effect to the Act's expansive definition of the term. Third, the Court of Appeals held that because the Industrial Stormwater Rule makes cross-reference to Standard Industrial Classification 24, the discharges at issue are “associated with industrial activity” within the meaning of the regulation, despite the EPA's conclusion to the contrary. The regulation was held to be unambiguous on this point. The Court of Appeals thus ruled that the discharges were from point sources and not exempt from the NPDES permitting scheme by the Industrial Stormwater Rule. It followed that petitioners had been in violation of the Act. . . .

II

Before proceeding to the merits, it is necessary to consider two jurisdictional questions.

[The Court then decided that the case was properly brought under the citizen suit provisions of 33 U.S.C. § 1365(a) and is not barred by §1369(b) as an untimely challenge to the original Silvicultural Rule. The Court also decided that the case was not rendered moot by EPA’s issuance of a new Silvicultural Rule because past discharges might be the basis for the imposition of penalties even if, in the future, those types of discharges would not require a permit.] . . .

III

The substantive question of the necessity for an NPDES permit under the earlier rule now must be addressed. Under the Act, petitioners were required to secure NPDES permits for the discharges of channeled stormwater runoff only if the discharges were “associated with industrial activity,” 33 U.S.C. § 1342(p)(2)(B), as that statutory term is defined in the preamendment version of the Industrial Stormwater Rule, 40 C.F.R. § 122.26(b)(14) (2006). Otherwise, the discharges fall within the Act's general exemption of “discharges composed entirely of stormwater” from the NPDES permitting scheme. 33 U.S.C. § 1342(p)(1).

NEDC first contends that the statutory term “associated with industrial activity” unambiguously covers discharges of channeled stormwater runoff from logging roads. That view, however, overlooks the multiple definitions of the terms “industrial” and “industry.” These words can refer to business activity in general, yet so too can they be limited to “economic activity concerned with the processing of raw materials and manufacture of goods in factories.” Oxford Dict. 887. The latter definition does not necessarily encompass outdoor timber harvesting. The statute does not foreclose more specific definition by the agency, since it provides no further detail as to its intended scope.

Somewhat more plausible is NEDC's claim that the preamendment version of the Industrial Stormwater Rule unambiguously required a permit for the discharges at issue. NEDC reasons that under the rule, “[f]or the categories of industries identified in this section,” NPDES permits are required for, among other things, “storm water discharges from ... immediate access roads ... used or traveled by carriers of raw materials.” 40 C.F.R. § 122.26(b)(14) (2006). Yet this raises the question whether logging is a “categor[y] of industr[y]” identified by the section. The regulation goes on to identify a list of “categories of facilities” that “are considered to be engaging in ‘industrial activity’ for purposes” of the Industrial Stormwater Rule. Ibid. In the earlier version of the regulation, this list included “[f]acilities classified as Standard Industrial Classificatio[n] 24,” which encompasses “Logging.” Ibid. Hence, NEDC asserts, logging is among the categories of industries for which “storm water discharges from ... immediate access roads ... used or traveled by carriers of raw materials” required NPDES permits under the earlier version of the Industrial Stormwater Rule. § 122.26(b)(14). NEDC further notes, in support of its reading of the regulation, that modern logging is a large-scale, highly mechanized enterprise, using sophisticated harvesting machines weighing up to 20 tons.

The EPA takes a different view. It concludes that the earlier regulation invoked Standard Industrial Classification 24 “ ‘to regulate traditional industrial sources such as sawmills.’ ” It points to the regulation's reference to “facilities” and the classification's reference to “establishments,” which suggest industrial sites more fixed and permanent than outdoor timber-harvesting operations. Ibid. See also 55 Fed.Reg. 47990, 48008 (1990). This reading is reinforced by the Industrial Stormwater Rule's definition of discharges associated with industrial activity as discharges “from any conveyance that is used for collecting and conveying storm water and that is directly related to manufacturing, processing or raw materials storage areas at an industrial plant.” 40 C.F.R. § 122.26(b)(14) (2006). This language lends support to the EPA's claim that the regulation does not cover temporary, outdoor logging installations. It was reasonable for the agency to conclude that the conveyances at issue are “directly related” only to the harvesting of raw materials, rather than to “manufacturing,” “processing,” or “raw materials storage areas.” See Oxford Dict. 1066 (manufacturing is “mak[ing] (something) on a large scale using machinery”); id., at 1392 (processing is “perform [ing] a series of mechanical or chemical operations on (something) in order to change or preserve it”). In addition, even if logging as a general matter is a type of economic activity within the regulation's scope, a reasonable interpretation of the regulation could still require the discharges to be related in a direct way to operations “at an industrial plant” in order to be subject to NPDES permitting.

NEDC resists this conclusion, noting that elsewhere in the Industrial Stormwater Rule the EPA has required NPDES permits for stormwater discharges associated with other types of outdoor economic activity. See § 122.26(b)(14)(iii) (mining); § 122.26(b)(14)(v) (landfills receiving industrial waste); § 122.26(b)(14)(x) (large construction sites). The EPA reasonably could conclude, however, that these types of activities tend to be more fixed and permanent than timber-harvesting operations are and have a closer connection to traditional industrial sites. In light of the language of the regulation just discussed, moreover, the inclusion of these types of economic activity in the Industrial Stormwater Rule need not be read to mandate that all stormwater discharges related to these activities fall within the rule, just as the inclusion of logging need not be read to extend to all discharges from logging sites. The regulation's reach may be limited by the requirement that the discharges be “directly related to manufacturing, processing or raw materials storage areas at an industrial plant.” § 122.26(b)(14).

It is well established that an agency's interpretation need not be the only possible reading of a regulation—or even the best one—to prevail. When an agency interprets its own regulation, the Court, as a general rule, defers to it “unless that interpretation is ‘plainly erroneous or inconsistent with the regulation.’ ” The EPA's interpretation is a permissible one. Taken together, the regulation's references to “facilities,” “establishments,” “manufacturing,” “processing,” and an “industrial plant” leave open the rational interpretation that the regulation extends only to traditional industrial buildings such as factories and associated sites, as well as other relatively fixed facilities.

There is another reason to accord Auer deference to the EPA's interpretation: there is no indication that its current view is a change from prior practice or a post hoc justification adopted in response to litigation. The opposite is the case. The agency has been consistent in its view that the types of discharges at issue here do not require NPDES permits.

The EPA's decision exists against a background of state regulation with respect to stormwater runoff from logging roads. The State of Oregon has made an extensive effort to develop a comprehensive set of best practices to manage stormwater runoff from logging roads. These practices include rules mandating filtration of stormwater runoff before it enters rivers and streams, Ore. Admin. Rule 629–625–0330(4) (2012); requiring logging companies to construct roads using surfacing that minimizes the sediment in runoff, Rule 629–625–0700(2); and obligating firms to cease operations where such efforts fail to prevent visible increases in water turbidity, Rule 629–625–0700(3). Oregon has invested substantial time and money in establishing these practices. In addition, the development, siting, maintenance, and regulation of roads—and in particular of state forest roads—are areas in which Oregon has considerable expertise. In exercising the broad discretion the Clean Water Act gives the EPA in the realm of stormwater runoff, the agency could reasonably have concluded that further federal regulation in this area would be duplicative or counterproductive. Indeed, Congress has given express instructions to the EPA to work “in consultation with State and local officials” to alleviate stormwater pollution by developing the precise kind of best management practices Oregon has established here. 33 U.S.C. § 1342(p)(6).

3

The preamendment version of the Industrial Stormwater Rule, as permissibly construed by the agency, exempts discharges of channeled stormwater runoff from logging roads from the NPDES permitting scheme. As a result, there is no need to reach petitioners' alternative argument that the conveyances in question are not “pipe[s], ditch[es], channel[s], tunnel[s], conduit[s],” or any other type of point source within the Act's definition of the term. § 1362(14).

For the reasons stated, the judgment of the Court of Appeals is reversed, and the cases are remanded for proceedings consistent with this opinion.

It is so ordered.

Justice BREYER took no part in the consideration or decision of these cases.

The opinion concurring in part and dissenting in part raises serious questions about the principle set forth in Bowles v. Seminole Rock & Sand Co., 325 U.S. 410 (1945), and Auer v. Robbins, 519 U.S. 452 (1997). It may be appropriate to reconsider that principle in an appropriate case. But this is not that case.

Respondent suggested reconsidering Auer, in one sentence in a footnote, with no argument. Petitioners said don't do it, again in a footnote. Out of 22 amicus briefs, only two—filed by dueling groups of law professors—addressed the issue on the merits.

The issue is a basic one going to the heart of administrative law. Questions of Seminole Rock and Auer deference arise as a matter of course on a regular basis. The bar is now aware that there is some interest in reconsidering those cases, and has available to it a concise statement of the arguments on one side of the issue.

I would await a case in which the issue is properly raised and argued. The present cases should be decided as they have been briefed and argued, under existing precedent.

I join Parts I and II of the Court's opinion; I agree that these cases are not moot and that the District Court had jurisdiction. I do not join Part III. The Court there gives effect to a reading of EPA's regulations that is not the most natural one, simply because EPA says that it believes the unnatural reading is right. It does this, moreover, even though the agency has vividly illustrated that it can write a rule saying precisely what it means—by doing just that while these cases were being briefed.

Enough is enough.

I

For decades, and for no good reason, we have been giving agencies the authority to say what their rules mean, under the harmless-sounding banner of “defer[ring] to an agency's interpretation of its own regulations.” This is generally called Seminole Rock or Auerdeference.

Two Terms ago, in my separate concurrence in Talk America, I expressed doubts about the validity of this practice. In that case, however, the agency's interpretation of the rule was also the fairest one, and no party had asked us to reconsider Auer. Today, however, the Court's deference to the agency makes the difference (note the Court's defensive insistence that the agency's interpretation need not be “the best one”). And respondent has asked us, if necessary, to “ ‘reconsider Auer.’ ” I believe that it is time to do so. This is especially true because the circumstances of these cases illustrate Auer’s flaws in a particularly vivid way.

The canonical formulation of Auer deference is that we will enforce an agency's interpretation of its own rules unless that interpretation is “plainly erroneous or inconsistent with the regulation.” But of course whenever the agency's interpretation of the regulation is different from the fairest reading, it is in that sense “inconsistent” with the regulation. Obviously, that is not enough, or there would be nothing for Auer to do. In practice, Auer deference is Chevron deference applied to regulations rather than statutes. The agency's interpretation will be accepted if, though not the fairest reading of the regulation, it is a plausible reading—within the scope of the ambiguity that the regulation contains.

Our cases have not put forward a persuasive justification for Auerdeference. The first case to apply it, Seminole Rock, offered no justification whatever—just the ipse dixit that “the administrative interpretation ... becomes of controlling weight unless it is plainly erroneous or inconsistent with the regulation.” 325 U.S., at 414. Our later cases provide two principal explanations, neither of which has much to be said for it., some cases say that the agency, as the drafter of the rule, will have some special insight into its intent when enacting it. The implied premise of this argument—that what we are looking for is the agency's intent in adopting the rule—is false. There is true of regulations what is true of statutes. As Justice Holmes put it: “[w]e do not inquire what the legislature meant; we ask only what the statute means.” The Theory of Legal Interpretation, 12 Harv. L.Rev. 417, 419 (1899). Whether governing rules are made by the national legislature or an administrative agency, we are bound by what they say, not by the unexpressed intention of those who made them.

The other rationale our cases provide is that the agency possesses special expertise in administering its “ ‘complex and highly technical regulatory program.’ ” That is true enough, and it leads to the conclusion that agencies and not courts should make regulations. But it has nothing to do with who should interpret regulations—unless one believes that the purpose of interpretation is to make the regulatory program work in a fashion that the current leadership of the agency deems effective. Making regulatory programs effective is the purpose of rulemaking, in which the agency uses its “special expertise” to formulate the best rule. But the purpose of interpretation is to determine the fair meaning of the rule—to “say what the law is,” Marbury v. Madison, 1 Cranch 137, 177 (1803). Not to make policy, but to determine what policy has been made and promulgated by the agency, to which the public owes obedience. Indeed, since the leadership of agencies (and hence the policy preferences of agencies) changes with Presidential administrations, an agency head can only be sure that the application of his “special expertise” to the issue addressed by a regulation will be given effect if we adhere to predictable principles of textual interpretation rather than defer to the “special expertise” of his successors. If we take agency enactments as written, the Executive has a stable background against which to write its rules and achieve the policy ends it thinks best.

Another conceivable justification for Auerdeference, though not one that is to be found in our cases, is this: If it is reasonable to defer to agencies regarding the meaning of statutes that Congress enacted, as we do per Chevron, it is a fortiori reasonable to defer to them regarding the meaning of regulations that they themselves crafted. To give an agency less control over the meaning of its own regulations than it has over the meaning of a congressionally enacted statute seems quite odd.

But it is not odd at all. The theory of Chevron (take it or leave it) is that when Congress gives an agency authority to administer a statute, including authority to issue interpretive regulations, it implicitly accords the agency a degree of discretion, which the courts must respect, regarding the meaning of the statute. While the implication of an agency power to clarify the statute is reasonable enough, there is surely no congressional implication that the agency can resolve ambiguities in its own regulations. For that would violate a fundamental principle of separation of powers—that the power to write a law and the power to interpret it cannot rest in the same hands. . . . Congress cannot enlarge its own power through Chevron—whatever it leaves vague in the statute will be worked out by someone else. Chevron represents a presumption about who, as between the Executive and the Judiciary, that someone else will be. (The Executive, by the way—the competing political branch—is the less congenial repository of the power as far as Congress is concerned.) So Congress's incentive is to speak as clearly as possible on the matters it regards as important.

But when an agency interprets its own rules—that is something else. Then the power to prescribe is augmented by the power to interpret; and the incentive is to speak vaguely and broadly, so as to retain a “flexibility” that will enable “clarification” with retroactive effect. “It is perfectly understandable” for an agency to “issue vague regulations” if doing so will “maximiz[e] agency power.” Combining the power to prescribe with the power to interpret is not a new evil: Blackstone condemned the practice of resolving doubts about “the construction of the Roman laws” by “stat[ing] the case to the emperor in writing, and tak[ing] his opinion upon it.” 1 W. Blackstone, Commentaries on the Laws of England 58 (1765). And our Constitution did not mirror the British practice of using the House of Lords as a court of last resort, due in part to the fear that he who has “agency in passing bad laws” might operate in the “same spirit” in their interpretation. The Federalist No. 81, pp. 543–544 (J. Cooke ed. 1961). Auer deference encourages agencies to be “vague in framing regulations, with the plan of issuing ‘interpretations' to create the intended new law without observance of notice and comment procedures.” Anthony, The Supreme Court and the APA: Sometimes They Just Don't Get It, 10 Admin. L.J. Am. U. 1, 11–12 (1996). Aueris not a logical corollary toChevron but a dangerous permission slip for the arrogation of power.

It is true enough that Auer deference has the same beneficial pragmatic effect as Chevron deference: The country need not endure the uncertainty produced by divergent views of numerous district courts and courts of appeals as to what is the fairest reading of the regulation, until a definitive answer is finally provided, years later, by this Court. The agency's view can be relied upon, unless it is, so to speak, beyond the pale. But the duration of the uncertainty produced by a vague regulation need not be as long as the uncertainty produced by a vague statute. For as soon as an interpretation uncongenial to the agency is pronounced by a district court, the agency can begin the process of amending the regulation to make its meaning entirely clear. The circumstances of this case demonstrate the point. While these cases were being briefed before us, EPA issued a rule designed to respond to the Court of Appeals judgment we are reviewing. It did so (by the standards of such things) relatively quickly: The decision below was handed down in May 2011, and in December 2012 the EPA published an amended rule setting forth in unmistakable terms the position it argues here. And there is another respect in which a lack of Chevron-type deference has less severe pragmatic consequences for rules than for statutes. In many cases, when an agency believes that its rule permits conduct that the text arguably forbids, it can simply exercise its discretion not to prosecute. That is not possible, of course, when, as here, a party harmed by the violation has standing to compel enforcement.

In any case, however great may be the efficiency gains derived from Auer deference, beneficial effect cannot justify a rule that not only has no principled basis but contravenes one of the great rules of separation of powers: He who writes a law must not adjudge its violation.

II

I would therefore resolve these cases by using the familiar tools of textual interpretation to decide: Is what the petitioners did here proscribed by the fairest reading of the regulations? What they did was to channel stormwater runoff from logging roads without a permit. To decide whether that was permissible we must answer one, and possibly two, questions: First, was the stormwater discharged from a “point source”? If not, no permit was required. But if so, we face the second question: Were the stormwater discharges exempt from the permit requirement because they were not “associated with industrial activity”? The fairest reading of the statute and regulations is that these discharges were from point sources, and were associated with industrial activity.

A

The Clean Water Act generally prohibits discharging pollution without a permit from what it calls a “point source.” 33 U.S.C. § 1311(a). A “point source” is defined as “any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, conduit,” and several other things. § 1362(14). The stormwater here was discharged from logging roads through a series of pipes, ditches, and channels—all items expressly named in the definition.

EPA argues that the Silvicultural Rule, 40 C.F.R. § 122.27(b)(1) (2006), excludes from the definition of “[s]ilvicultural point source” “harvesting operations ... from which there is natural runoff.” This is relevant, says the agency, because that rule specifies that only “[s]ilvicultural point sources, as defined in this section,” are “point sources subject to the ... permit program.” § 122.27(a). In EPA's view, the stormwater here is “natural runoff.”

But are stormwater discharges “natural runoff” when they are channeled through manmade pipes and ditches, and carry with them manmade pollutants from manmade forest roads? It is not obvious that this is so—as the agency agrees. In my view, giving the term the agency's interpretation would contradict the statute's definition of “point source,” which explicitly includes any “pipe, ditch, channel, tunnel, [and] conduit.” Applying the interpretive presumption of validity—the canon that we are to “prefe[r] the meaning that preserves to the meaning that destroys”—I would hold that the regulation's exclusion of “natural runoff” does not reach the situation here. The stormwater discharges came from point sources, because they flowed out of artificial “pipe[s],” “ditch[es],” and “channel[s],” 33 U.S.C. § 1362(14), and were thus not “natural runoff” from a logging operation, 40 C.F.R. § 122.27(b)(1) (emphasis added).

B

Many point-source stormwater discharges are nonetheless exempt from the usual permitting requirement. See 33 U.S.C. § 1342(p). This exemption, however, does not reach discharges “associated with industrial activity.” Ibid. EPA has enacted a rule defining what it means for stormwater discharges to be “associated with” industrial activity, and what activities count as “industrial.” 40 C.F.R. § 122.26(b)(14).

The regulation sets out eleven “categories of industries”; as to those industries, discharges are “associated with industrial activity” if they come from sites used for “transportation” of “any raw material.” Ibid. The forest roads at issue here are used to transport raw material (logs); the only question is whether logging is a “categor[y] of industr[y]” enumerated in the definition. It is: The second of the listed “categories of facilities” is “[f]acilities classified as Standard Industrial Classifications 24 (except 2434).” § 122.26(b)(14)(ii). Opening one's hymnal to Standard Industrial Classification 24 (“Lumber and Wood Products, Except Furniture”), one finds that the first industry group listed, No. 2411, is “Logging”—defined as “[e]stablishments primarily engaged in cutting timber.” 2 App. 64. (As if that were not clear enough, an illustrative product of this industry is helpfully listed: “Logs.”) That, I would think, is that.

EPA disagrees, and the Court gives the agency's position Auerdeference, but that reading is certainly not the most natural one. The Court relies heavily on the fact that the definition of “[s]torm water discharge associated with industrial activity” requires that the discharge be “directly related to manufacturing, processing or raw materials storage areas at an industrial plant,” § 122.26(b)(14). The crucial question this definition presents is whether the concluding phrase “at an industrial plant” limits only the last noun phrase (“raw materials storage areas”) or also the two preceding nouns (“manufacturing” and “processing”). The canon of interpretation known as the rule of the last antecedent states that “a limiting clause or phrase ... should ordinarily be read as modifying only the noun or phrase that it immediately follows.” If a statute provides that “it shall be unlawful to possess a grenade launcher, a fully-automatic weapon, or a shotgun with a barrel shorter than 12 inches,” that does not mean that a grenade launcher with a barrel longer than 12 inches is legal. Application of the canon would mean that “at an industrial plant” modifies only “raw materials storage areas,” and therefore that “manufacturing” and “processing” anywhere, including in the forest, would be “associated with industrial activity.” (Standard Industrial Classification 24 categorizes logging as a manufacturing business, and these discharges are therefore “directly related to manufacturing.”)

Like all canons of interpretation, the rule of the last antecedent can be overcome by textual indication of contrary meaning. But that does not exist here. To the contrary, the enumerated categories of industries to which the term “industrial activity” applies reinforce the proposition that “at an industrial plant” does not modify “manufacturing” or “processing.” The term includes (in addition to logging) “active or inactive mining operations,” § 122.26(b)(14)(iii); “[l]andfills” and “open dumps,” § 122.26(b)(14)(v); “automobile junkyards,” § 122.26(b)(14)(vi); and “[c]onstruction activity including clearing, grading and excavation,” § 122.26(b)(14)(x). Those industries and activities (while related to manufacturing and processing) virtually never take place at anything like what one might describe as a “plant.” The rule of the last antecedent is therefore confirmed as the correct guide to meaning here: “at an industrial plant” limits only “raw materials storage areas.”

EPA also insists that the regulation reaches only “ ‘traditional’ ” sources of industrial stormwater, such as sawmills. But Standard Industrial Classification 24 has a specific subcategory (No. 242) that is “Sawmills and Planing Mills.” 2 App. 64. The rule is not so limited, reaching by its terms “Standard Industrial Classificatio[n] 24 (except 2434).” § 122.26(b)(14)(ii). The explicit carving-out of No. 2434 is telling: Why EPA chose to exclude “establishments primarily engaged in manufacturing wood kitchen cabinet and wood bathroom vanities” from the definition of industrial stormwater, I do not know—but the picayune nature of the exclusion gives lie to the idea that the rule's scope ought to be decided by a rough sense of its gestalt. If EPA had meant to reach only sawmills, it quite obviously knew how to do so.

Finally, the Court believes that Standard Industrial Classification 24's reference to “establishments” “suggest[s] industrial sites more fixed and permanent than outdoor timber-harvesting operations.” Not so. The Standard Industrial Classification uses “establishments” throughout to refer to business entities in general; for example, Classification 2411 refers to “[e]stablishments primarily engaged in cutting timber,” which includes “producing wood chips in the field.” I cannot imagine what kind of “fixed and permanent” industrial site the Court and EPA imagine will be “producing wood chips in the field.” And the Court's final point—that the regulatory definition of “industrial activity” uses the word “facilities”—cuts the other way: EPA regulations define “facility” to include “any ... ‘point source.’ ” 40 C.F.R. § 122.2; see, e.g., § 122.26(b)(14)(iii) (referring to mines as “facilities”).

The agency also assures us that its intent was to reach a more limited subset of logging activities, an intent that it believes can essentially float free from the text of the relevant rule. In the end, this is the real meat of the matter: EPA states that it simply did not mean to require permits for the discharges at issue here. And the Court is willing to credit that intent, even given what I think has been amply demonstrated to be a contrary text.

III

Because the fairest reading of the agency's rules proscribes the conduct at issue in these cases, I would affirm the judgment below. It is time for us to presume (to coin a phrase) that an agency says in a rule what it means, and means in a rule what it says there.

Pages 767-778: TOTAL MAXIMUM DAILY LOADINGS (TMDLs)

On July 6, 2015, the U.S. Court of Appeals for the Third Circuit unanimously upheld EPA’s TMDL for the Chesapeake Bay. In American Farm Bureau Federation v. U.S. EPA 792 F.3d 281 (3rd Cir. 2015), the court affirmed a decision by a federal district court that had found the TMDL to be reasonable in allocating pollution reductions among point and nonpoint sources, determined that the TMDL was not an unlawful federal implementation plan, and upheld the procedures and models used in establishing the TMDL. 984 F.Supp. 2d 289 (M.D. Pa. 2013). The Third Circuit panel described the district court’s decision as “careful and thorough.” It concluded: “Congress made a judgment in the Clean Water Act that the states and the EPA could, working together, best allocate the benefits and burdens of lowering pollution. The Chesapeake Bay TMDL will require sacrifice by many, but that is a consequence of the tremendous effort it will take to restore health to the Bay—to make it once again a part of our “land of living,” Robert Frost, The Gift Outright line 10—a goal our elected representatives have repeatedly endorsed. Farm Bureau’s arguments to the contrary are unpersuasive, and thus we affirm the careful and thorough opinion of the District Court.” A copy of the Third Circuit’s opinion is available online at: http://www2.ca3.uscourts.gov/opinarch/134079p.pdf.

The American Farm Bureau Federation (AFBF) then sought Supreme Court review of the decision. The AFBF argued that EPA had exceeded its authority by determining how to allocate the pollution reductions between types of pollution. The TMDL seeks to reduce nitrogen runoff by 25%, phosphorus by 24% and sediment by 20% from 2010 levels by 2025. Sixty percent of these reductions are to be achieved by 2016. The AFBF argues that this means that 20% of land adjoining the Bay that currently is used for agriculture production will have to be taken out of production. On February 29, 2016, the U.S. Supreme Court denied review of the Third Circuit’s decision.

On May 31, 2016 the U.S. Supreme Court ruled unanimously that jurisdictional determinations (JDs) by the U.S. Army Corps of Engineers that property contains wetlands subject to § 404 of the Clean Water Act are judicially reviewable. The decision in U.S. Army Corps of Engineers v. Hawkes, Inc. was not a surprise, even though most U.S. Courts of Appeals had ruled that the issuance of a JD did not trigger judicial review. In a majority opinion written by Chief Justice Roberts, the Court held that the issuance of a JD is “final agency action” that may be challenged in court under the Administrative Procedure Act because it is definitive in nature and has direct legal consequences. The Chief Justice noted that a memorandum of understanding between the Corps and EPA makes a JD binding on both agencies for five years. An extraordinary concurring opinion by Justice Kennedy, joined by Justices Thomas and Alito, harshly criticized the “ominous reach” of the Clean Water Act (CWA) and stated that the CWA “continues to raise troubling questions regarding the Government’s power to cast doubt on the full use and enjoyment of private property throughout the Nation.” An edited copy of the decision is contained in our 2016-17 Statutory and Case Supplement.